Educational Articles

Cats + Parasites

  • Atovaquone is given by mouth and is used off-label to treat protozoal infections. Give as directed. Side effects are uncommon but may include stomach upset or skin rash. Do not use in pets that are pregnant. If a negative reaction occurs, contact your veterinarian as soon as possible.

  • Azithromycin is given by mouth or injection and is used on and off-label to treat a variety of infections. Give as directed. Common side effects include stomach upset. Do not use in pets that are sensitive to macrolide antibiotics. If a negative reaction occurs, please call your veterinary office.

  • Capillaria is a small internal parasite, often less than half of a centimeter in length. They are closely related to intestinal worms, though they can live in a variety of locations within the body. Capillaria can affect both dogs and cats, although dogs are more frequently affected. Diagnosis can be difficult because the eggs of Capillaria are shed only on an intermittent basis. While the parasite is easily eliminated with a dewormer, your cat may require additional medications to decrease the inflammation associated with the infection.

  • Coccidia are single-celled organisms that can act as a parasite after infecting your cat through the gastrointestinal tract. The most common form affecting cats, Isospora, is not a concern for infecting people, unlike Toxoplasma. They are highly resistant to environmental conditions, so cleanliness is important to prevent re-infection. Treatment is often simple with the appropriate antibiotics prescribed by your veterinarian.

  • Cuterebra is the scientific name for the North American rabbit or rodent botfly. Cats are accidental hosts of Cuterebra larvae, and they are rarely evident from external skin inspection. A hole enlarges when the warble has matured, often leading to an infected empty cyst. Treatment depends on when the condition is discovered, and in many cases, antibiotics are used to treat secondary infections.

  • Cytauxzoonosis is an often-fatal disease caused by a tick-borne protozoan parasite, typically found in bobcats. It is more commonly seen in the southern United States but is spreading with tick migration. It can cause anorexia, lethargy, respiratory difficulty, anemia, and jaundice. Diagnostic testing, treatment options, and preventives are described in this handout. This disease is not transmissible to dogs or humans.

  • The ear mite is a surface mite that lives on cats, dogs, rabbits, and ferrets. It is usually found in the ear canal but it can also live on the skin surface. Mites are barely visible to the naked eye. Clinical signs of infestation vary in severity and may include ear irritation, leading to scratching at the ears or head shaking, dark waxy or crusty discharge from the ear, areas of hair loss resulting from self-trauma, a crusted rash around or in the ear, and an aural hematoma. Your veterinarian will advise you about which insecticidal products are suitable. Your veterinarian may want to re-examine your pet to ensure that the mites have been eliminated after the initial treatment has been performed.

  • Esafoxolaner + eprinomectin + praziquantel is given topically on the skin to treat and protect against various internal and external parasites and prevent heartworm in cats. Side effects are rare but may include hair loss at the application site, gastrointestinal upset, skin reactions, or neurologic signs. Use caution in sick or underweight cats. If a negative reaction occurs, please call your veterinary office.

  • Demodicosis is a parasitic skin condition caused by Demodex mites. These microscopic mites can be found on the skin of all animals but, in some cases, they multiply to excessive levels and cause clinical signs. Signs vary depending on the species of mite involved, though generally involve hair loss, skin inflammation, and crusting. Demodex mites found on cats and dogs do not spread to humans.

  • Despite common belief, an average cat experiences only minor skin irritation in response to flea bites. Even in the presence of dozens of fleas, there will typically be minimal itching. On the other hand, a cat with flea allergies will have a severe reaction to even a single flea bite. Affected cats experience intense itching and will chew, lick, or scratch the affected site(s) nonstop, causing hair loss and possibly open sores or scabs on the skin, allowing a secondary bacterial infection to develop. Strict flea control is the foundation of successful treatment. There are many highly effective flea control products for treating the cat and controlling fleas in the environment.

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